By which process is $CO_2$ not added into the atmosphere?

Out of the two statements given here $:-$
$(A) \ C_4$ plants are more effective in productivity as compared to $C_3$ plants.
$(B) \ C_3$ plants show photorespiration at high $CO_2$ concentration.

$A$ photosystem is composed of $..............$.

Anoxygenic photosynthesis is characteristic of

Photosynthesis is a:

Select the correct statement.